A quarantine was a restriction placed upon movement.
Having taken the Doctor's TARDIS on board their probe ship, the Morestran crew had it placed in quarantine. When Sarah Jane Smith exited the TARDIS, Controller Salamar had oxygen transferred into the quarantined area, recognising her dependency upon it. (TV: Planet of Evil)
In 51st century, the Tenth Doctor advised River Song to set up a quarantine beacon on the Library to ward away would-be visitors lest they come into contact with the Vashta Nerada. (TV: Silence in the Library)
In 5,000,000,023, when the Sisters of Plenitude's diseased test subjects broke out, Matron Casp ordered that the New New York Hospital be placed under maximum quarantine, resulting in incoming shuttles being diverted and all lifts being shut down. Frau Clovis attempted to override the quarantine and get a signal to New New York, though the Tenth Doctor warned that any forced entry would break the quarantine. Ultimately, the crisis was averted when the Doctor concocted a cocktail of medicines to cure the patients. (TV: New Earth)
In 5,000,000,029, in response to the Bliss virus, the New Earth Senate's last act was to establish an quarantine which sealed the undercity while the surface population all but perished, taking the virus with it. Being an automatic quarantine, it would have lasted 100 years, however, in 5,000,000,053, the Tenth Doctor and tthe Face of Boe, the people on the motorway by unsealing the exits and opening the roof section, allowing those trapped to escape and repopulate the city. (TV: Gridlock)